I've stated this several times, now with a different twist. By adding through the skimmer, which I always do, the bleach is diluted immediately although the concentration is still high, but the time in contact with any circulation components is small. Consider normal chlorinated pool water that is in contact 24/7. Now you have a high concentration of chlorine in contact for maybe 2 minutes at the most if you pour really slow? Nothing will happen.
Al